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among the plants. The generic name, however, having once been 
used in the animal kingdom for one organism, can not be used for 
any other organism classified as an animal, despite the fact that the 
original Coccidioides is no longer viewed as an animal. The names 
Bacillus , Bacterium , Spirillum , Spirochdeta , and Vibrio are of interest 
in this general connection, since the bacteria were first classified as 
animals, later as plants, while Spirochdeta has now been transferred 
again to zoology. 
Spirochdeta Ehrenberg, 1831a, 169, was proposed as a genus of 
protozoa; it was then classified among the plants; more recently it has 
been returned to the animal kingdom. Although for years this genus 
was classified among the plants, it still retained its zoological status. 
This case will illustrate the necessity for the rule given above. Had 
zoologists admitted Spirochdeta as valid for some new genus (cf. 
Spirochdeta Sars., 1856, a worm) on the ground that the original 
Spirochdeta had been eliminated from the animal kingdom, it would 
now be necessaiy to change the name of the later Spirochdeta genus 
upon the return of Spirochdeta , 1831, to the animal kingdom. 
Art. 2. The scientific designation of animals is uninominal for sub- 
genera and all higher groups, binominal for species, and trinominal 
for subspecies. 
Discussion. — Prior to the introduction of the Linnsean system of 
nomenclature, organisms were generally given a polynominal name, 
which in many cases was identical with the description. The Linnsean 
system introduced into zoology and botany the custom of using two 
names, hence it is frequently called the “binomial” system. These 
names referred to two things, or two systematic units (namely, the 
genus and the species), hence the Linnaean method is frequently known 
as the “binary 1 ’ system. One of these names is the generic name 
(corresponding to the family name or surname of persons), the 
other is the specific name (corresponding to the Christian name of 
persons). Thus, man as a systematic unit is known as Homo sapiens; 
the tiger is Felis tigris , the lion Felis leo. In the case of the feline 
animals, Felis is the generic name (corresponding to the family" name 
Smith), while tigris and leo are specific names (corresponding to John , 
Frank , Mary , etc.). When the generic name is combined with a 
specific name, as Felis tigris , the combination is known as the 
“ binomial.” 
In some instances it is convenient to recognize a systematic unit of 
lower value than the species; such units are known as subspecies. 
Thus, the wild boar is known as Sus scrofa; but the domesticated hog 
is recognized as more or less distinct from the boar, yet not sufficiently 
distinct to be given full specific rank. It is classified as a subspecies, 
Sus scrofa domestica , the combination of the generic, the specific, and 
the subspecific names representing the “trinomial.” 
